ETH - Zurich

The architect’s intention was to create a reinforced concrete structure and to shield the interior of the building from the sun’s rays through the use of a series of travertine panels, which during the day would create a play of light and shadow within.

The first issue was to satisfy the request of the studio that the slabs should be of one piece. All the suppliers contacted by the studio and the installation company refused the commission citing the dimensions (average length 460 cm) and the weight (almost 1.5 tons) and stating that conditions in the quarry and, above all, the limits of the marble cutting machines made it impossible to manage slabs of these dimensions. Everyone contacted advised dividing the slabs into two or three pieces and then joining them mechanically.

After an initial evaluation by our technical department, we decided to modify the cutting machine by dismantling the saw blade limiters and welding steel extensions onto these, allowing us to cut slabs of up to a length of 5 metres and so comply with the aesthetic intent of the architect. Each slab was then drilled into from above and below in order to insert 120 mm steel cylinders that were then fixed to the slab in reinforced concrete. In order to then satisfy the desire of the architect to create a material surface, we selected a specific bank of the quarry where the holes were not excessively large. This allowed us to add a surface finish created specifically for the project. In addition, based on the climatic conditions surrounding the structure, we put the material through a cycle of freezing and thawing and mechanical testing to simulate resistance of the natural ageing of the stone.

The slabs need to be lifted to a height of over 20 metres.

After a careful analysis, in collaboration with the installation company we created a special counterweighted pincer to enable the slab to be turned 180° with minimal effort and to be positioned over the steel cylinders. The work was completed without difficulty and ahead of schedule. In addition to the supply of over 1,000 cladding slabs, we also supplied over 12,000 square metres of paving and internal cladding, including the stairs.


DESIGNER: Baumschlager Eberle